Quick Homework Help

# x + 3y = 18 2x + y = 11 ⚑ Flag

by Jide001 at February 18, 2010

9+3(3)=18 2(4)+3=11

jorge.jk February 18, 2010

x + 3y = 182x + y = 11A fun way to solve this problem is to perform an operation to make one of the variables from both equations to zero out, and then solve for the remaining variable.x + 3y = 18-3(2x + y = 11)distribute -3 across the equation:-6x - 3y = -33x + 3y = 18simplify:-5x = -15divide each side by -5 to isolate and solve for x:-5x/-5 = -15/-5; perform division operation:x = 3, now substitute the value of x into the equation:3 + 3y = 18subtract 3 from each side of the equation:3y = 15; divide by 3 to solve for y:y = 5The solution set is: (3,5)

Steven401 October 22, 2010

Another fun way to solve the problem where:x + 3y = 18, and2x + y = 11, is to put them into their slope intercept form and then plot the respective equations coordinates on graph paper. Remember that the slope intercept format is: y = mx + b, where y is a dependent variable, x is the independent variable, m is the slope of the line, and b is the y-intercept, the x-intercept can be calculated by solving the equation when y = 0. Here goes:x + 3y = 18, 3y = -x + 18, y = -1/3 x + 6, so here's what we know: the slope is -1/3 (meaning that the slope is very gentle where the rise is negative 1/3 and the run is 1) , the y-intercept is 6, the x-intercept is 18. Graph it. Second equation: 2x + y = 11, y = -2x +11; we know: the slope is -2, (rise is negative 2, run is 1, so a steeper slope) y-intercept is 11, x-intercept is 5.5. Graph it on the same graph paper. Determine point of intersection: (3,5)

Steven401 October 22, 2010